<?php

/*
	Question2Answer (c) Gideon Greenspan

	http://www.question2answer.org/

	
	File: qa-include/qa-db-limits.php
	Version: See define()s at top of qa-include/qa-base.php
	Description: Database-level access to tables which monitor rate limits


	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.
	
	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	More about this license: http://www.question2answer.org/license.php
*/

if (!defined('QA_VERSION')) { // don't allow this page to be requested directly from browser
    header('Location: ../');
    exit;
}


function qa_db_limits_get($userid, $ip, $action)
    /*
        Get rate limit information for $action from the database for user $userid and/or IP address $ip, if they're set.
        Return as an array with the limit type in the key, and a labelled array of the period and count.
    */
{
    $selects = array();
    $arguments = array();

    if (isset($userid)) {
        $selects[] = "(SELECT 'user' AS limitkey, period, count FROM ^userlimits WHERE userid=$ AND action=$)";
        $arguments[] = $userid;
        $arguments[] = $action;
    }

    if (isset($ip)) {
        $selects[] = "(SELECT 'ip' AS limitkey, period, count FROM ^iplimits WHERE ip=COALESCE(INET_ATON($), 0) AND action=$)";
        $arguments[] = $ip;
        $arguments[] = $action;
    }

    if (count($selects)) {
        $query = qa_db_apply_sub(implode(' UNION ALL ', $selects), $arguments);
        return qa_db_read_all_assoc(qa_db_query_raw($query), 'limitkey');

    } else
        return array();
}


function qa_db_limits_user_add($userid, $action, $period, $count)
    /*
        Increment the database rate limit count for user $userid and $action by $count within $period
    */
{
    qa_db_query_sub(
        'INSERT INTO ^userlimits (userid, action, period, count) VALUES ($, $, #, #) ' .
            'ON DUPLICATE KEY UPDATE count=IF(period=#, count+#, #), period=#',
        $userid, $action, $period, $count, $period, $count, $count, $period
    );
}


function qa_db_limits_ip_add($ip, $action, $period, $count)
    /*
        Increment the database rate limit count for IP address $ip and $action by $count within $period
    */
{
    qa_db_query_sub(
        'INSERT INTO ^iplimits (ip, action, period, count) VALUES (COALESCE(INET_ATON($), 0), $, #, #) ' .
            'ON DUPLICATE KEY UPDATE count=IF(period=#, count+#, #), period=#',
        $ip, $action, $period, $count, $period, $count, $count, $period
    );
}


/*
	Omit PHP closing tag to help avoid accidental output
*/